A. Field of the Invention
The invention to which this application relates is to a bearing arrangement of the type which can be used particularly, although not necessarily exclusively, in power tools with a reciprocating blade such as jigsaws or scrollers in which the blade to reciprocate in a linear or pendular/orbital manner. The same are hereinafter referred to as jigsaws in a non-limiting manner.
B. Problems in the Art
The use of jigsaws is well known and they typically comprise the provision of a power source, such as an electric motor which acts to drive an elongate member, reciprocally, in a linear direction and/or in some cases, as in this invention, with a pendulum or swinging movement. Typically selection means are provided to allow the specific type of movement to be selected by the user.
Typically, the elongate member acts as a holder for a cutting blade which protrudes out from the housing of the power tool and the elongate member and motor are mounted within the housing. Typically, the linear movement is along a first linear axis. At a first end of the elongate member, the blade is mounted and, at the second, opposing end, a pivotal location is provided about which the elongate member moves when the pendulum movement is selected.
In order to ensure that the movement of the elongate member is controlled in the desired manner, first and second spaced bearings are typically provided. The first bearing is typically provided at or proximate to the said pivotal location, and in one embodiment, may include the pivot location. The second bearing is provided at a position along the elongate member spaced from the pivotal location and towards the location at which the blade is gripped to perform the cutting action.
The second bearing includes an aperture which is slotted with a first axis of the slot longer than a second axis of the slot which is perpendicular to the first axis. The shorter axis length is typically the same or close to the diameter of the member which passes through the aperture. This arrangement allows the member to swing along the first axis of the slot but movement of the member in the second axis, lateral to the swinging movement of the member, is substantially prevented.
However, a problem with this arrangement is that the longer axis of the slot allows the elongate member to be free to move in a relatively uncontrolled manner along a relatively long path which, although required when the same is moved in the pendulum manner, can mean that there is a lack of control of movement of the member in the linear reciprocating direction.